How to compare two bone?

How to compare two bone with a color map.

The method was discribled as follows:
The thickness was calculated using Scanco’s trabecular bone evaluation (Direct method). Color maps of the thickness were generated from the contoured subchondral bone plate of the operated and unoperated knees. To better visualize the thickened region post-DMM, the color legends were scaled to the maximum thickness detected in each age group.